Large scale data from a number of epidemiological studies is yielding valuable insights into incidence and prevalence of hearing loss in different cohorts.  As just one example, the National Health and Nutrition Examination Survey (NHANES) study data tells us that 93% of white men in the 60-69 age group have high frequency hearing loss and 43% have hearing loss in low and mid-frequencies.  That is just a peek at all that this wealth of longitudinal data is beginning to reveal about hearing loss, gender, aging, and a plethora of other health-related variables.

In recent years, studies have begun to plumb the epidemiological data for lifestyle links to hearing loss.  Exercise, social activities, work environments, and food choices are examples of lifestyle choices that could influence hearing health.  Information on results of such research can be  immediate importance to consumers and hearing healthcare providers, as well as other stakeholders, if is shown that improvements are possible as a part of daily life.  As one study puts it:

“Diet is one of the few modifiable risk factors for age-related hearing loss.”  (Gopinath et al 2011)

Antioxidants and vitamins, ingested via food or supplements, are obvious candidates for investigation.  The data are mountainous and the challenge of controlling covariance among a large number of variables demands careful study design and statistical analyses.  Different types of subjects in different numbers for different lengths of time comprise different data sets, which adds to the challenge.  Finally, hearing evaluation measurements were not top in the minds of those who designed baseline measures when the studies were initiated decades ago.  

As a result, the data may be (partially) in, but the results are just beginning to give us some idea of how or if vitamins and antioxidants are important to our hearing.  Today’s and next week’s posts look at what has come out of the studies to date.

 

Quick Statistics Primer

 

It’s not surprising that complex study designs and analyses test our ability to understand their findings and conclusions.  Most audiologists, in good company with most readers in general, do not have years of education in statistics.  It’s easier to interpret study findings if you have a good handle on definitions and terms which are common to researchers but not so commonly bandied about in clinical practices.  

Here are a few reminders that may prove helpful in reading the summary studies in the next sections.

Figure 1. Relative Risk illustration (from nutridesk.com)

  • Incidence: This is a proportion or percentage figure that is a measure of the risk of developing hearing loss in a time interval specified by the study.
  • Prevalence:  Another proportion or percentage, this figure states the portion of hearing loss in the study population at a given time.
  • Odds Ratio (OR): This states the odds that hearing loss occurs with an intervention (i.e., vitamin intake) compared to the odds of it occurring without the intervention (i.e., no vitamin). An OR = 1 means the odds are even and the intervention has no effect. A positive OR means the risk is heightened by the intervention; a negative OR means the risk is lowered.  NOTE:  Hi or low odds do not state or imply causality.  
  • Risk Ratio (RR): Also called the Relative Risk.  RR states the odds of hearing loss in one intervention group compared to other intervention groups over time. RR = 1 means even odds, same as OR.
  • Hazard Ratio (HR):  This is the same measure as RR but only at one point in time. HR is a measure of “instantaneous risk”, not cumulative risk over a time interval like OR and RR.  Like OR and RR, HR = 1 means even odds.
  • Confidence Level (CL)   The calculated probability that any of the ratios above are true. It’s needed because all data come from samples of an entire population. Large samples are better for estimating than small samples, but even large samples contain some degree of uncertainty.  A 95% CL means that there is a 95% probability that the HR, RR or OR is correctly reflecting the true population and is not in error.  
  • Confidence  Interval (CI): The Confidence Interval (CI) states the upper and lower value of the estimate. When the CL is 95%, the CI extends from 2.5% to 97.5% of the measurements.  

 

Three Studies of Hearing Loss and Dietary Risk Factors

 

Next week, we’ll compile some basic descriptors for the designs and findings of three important studies:

  1. Health Professionals Follow-up Study (Shargorodsky et al, 2010)
  2. Blue Mountains Hearing Study (Gopinath et al, 2011)
  3. Conservation of Hearing Study (Curhan et al, 2015)

Although the studies are monumental, they vary in scope, goals, length, etc., and each has limitations.  But in the aggregate, they lend support to the idea that vitamin antioxidants have some influence on hearing loss which deserves further study.  

 

References

 

Agrawal Y et al. Prevalence of hearing loss and differences by demographic characteristics among US adults: data from the National Health and Nutrition Examination Survey, 1999–2004. Arch Intern Med. 2008;168:1522–1530. 

Curhan SG et al.  Carotenoids, vitamin A, vitamin C, vitamin E, and folate and risk of self-reported hearing loss in women. Am J Clin Nutr. 2015 Nov; 102(5): 1167–1175. Published online 2015 Sep 9. doi:  10.3945/ajcn.115.109314 PMCID: PMC4625586

Gopinath B et al. Dietary antioxidant intake is associated with the prevalence but not incidence of age-related hearing loss. J Nutr Health Aging 2011;15:896–900.

Shargorodsky J et al. A prospective study of vitamin intake and the risk of hearing loss in men. Otolaryngol Head Neck Surg. 2010 Feb; 142(2): 231–236. doi:  10.1016/j.otohns.2009.10.049 PMCID: PMC2853884 NIHMSID: NIHMS180764

 

feature images from Inside Tracker

 

Over the years, The Audiology Condition has socked away items of interest for active Seniors who may find themselves consulting with Audiologists.  

The following are light-hearted articles but each contains a hearing nugget worth thinking about for active Seniors seeking hearing help.  

 

Seniors are the New Awesome

 

Back in the day, patients thought hearing loss meant they were old, so they said things like “I hear OK considering my age.” Believe it or not, a lot of these people were in there 60s and 70s, which is young now that Boomers are getting in that age bracket.  As one columnist cleverly puts it:

“Now we see ads featuring handsome, energetic 60-something retirees announcing that they are finally ready to live out their dreams and move to Peru or start a rock band in the garage. If they have that much energy, why not make them keep working?”

More and more Seniors  are working and don’t plan to stop. Many others are so busy traveling, golfing, socializing, volunteering that they don’t have time to work. None of these people consider themselves old, but many of them have hearing loss. They get hearing aids and learn to use them for the same reason they go to Pilates or yoga every week — to stay in the game.

As a result of their efforts and willingness to embrace change and new technologies, these people are not only in the game, they are winning the game.  But,  if you plan to start a rock band, please see your audiologist first to get fitted with appropriate ear protection.

 

Some Things Are Better the Old Fashioned Way

 

Texting has its uses and no one can live without email. But when it comes to good communication nothing beats old fashioned one-on-one spoken conversation, especially when it can be face-to-face. Not all conversations cannot be conducted face-to-face, hence the need for telecommunications.  

For many years before cell phones appeared, the telephone was the next-best thing to actually speaking with another person face-to-face. Cell phones are wonderful for extending the range over which these conversations can take place. But things have gotten out of whack as cell phones have assumed other roles in people’s lives, especially those of younger people.

Seniors have the advantage here because they actually know, or at least remember, how to conduct two-way conversations in person and on phones.  

We need to get back to the good old days of the “mystical magic of the mouth” as described in this hilarious video:  

 

Some Things Are Not Advisable, Even With Hearing Aids

 

Even if you DON’T have a hearing loss, you might need amplification or a speech reading class before flying first class on Virgin Atlantic. In what the airline calls its Upper Class, cabin crews began receiving receive special auditory training to coddle passengers back in 2012: 

Virgin Atlantic is sending senior members of its cabin crews on training courses to improve their whispering skills. Flight stewards who serve the airline’s Upper Class passengers will attend a day-long course with a “whispering coach”, where they will learn how to speak at a volume of less than 30 decibels. (Normal conversation is about 70 decibels.)  The airline said that quieter cabin crews would have a “calming effect” on passengers.”  (British Week, p 6, March 3 2012).

Forget the whispering coach — Virgin needs a hearing coach to advise them on decibels. If Virgin was thinking what we think they were thinking, trained flight attendants would be speaking below the thresholds of many normal listeners, defying the listening skills of almost everyone. Perhaps attendants were trained to place their lips in passengers’ ears, as part of Virgin coddling. That might or might not help, depending on the decibel level of “normal” whispered speech at the ear.   

No word since 2012 on how the Upper Class whispering campaign is going, or whether it’s even active anymore. But those with hearing loss may want to save money and book Business Class, where flight attendants will likely speak in audible tones if not in your ear.

 

Hearing Aids are for Real Men, Not Sissy Boys

 

You know you’ve hit the big time when Field and Stream’s Gun Nut blog writes a post about noise-induced hearing loss, fetchingly entitled “Hearing Loss:  Only You Can Prevent Brain Rot”:

“In [plain] English…if your ears are f***ed, pretty soon your brain will be, too. And while your ears can get help from hearing aids, there’s nothing that can be done for your rotten brain. As the audiologist put it, ‘Once you start sliding down that slope, you’re in real trouble.'”

 

HHTM editors never thought of saying it in plain English like that.  Thanks. Regardless of language, age, gender or travel habits, hearing loss is a slippery slope and that’s why The Audiology Condition keeps pounding away at the topic.